| Magnetic method
of flaw detection shall be employed wherever possible
for ferritic steel; |
Reg. 265 d
Dye-Penetrant flaw detection
|
Dye-Penetrants or equivalent method for flaw detection
shall be employed for Austenetic or other non-magnetic
steel.
|
Reg. 265 e
(e) All butt
welded joints shall be subjected to non-destructive
examination by radiographic, radioscopy or other approved
methods such as ultrasonic testing, magnetic particle
inspection or liquid dye penetrant inspection.
When radioscopic examination is to be performed in lieu
of radiography on welded components, the following
requirements shall be met, namely:-
(1)
A written procedure shall be submitted for approval to
the Inspecting Authority which shall contain the following:
(i)
material
and the thickness range;
(ii)
equipment qualifications;
(iii)
test object scan plan;
(iv)
radioscopic parameters;
(v)
image processing parameters;
(vi)
image display parameters;
(vii)
image archiving requirements;
(viii)
accept-reject criteria (Code reference);
(ix)
performance evaluation;
(x)
Operator identification.
(2)
The system shall be aided with an image processor to
enhance the quality of the radioscopic images and system
performance quality shall exhibit-
(i)
a thin section contrast sensitivity of 3%;
(ii)
a thick section contrast sensitivity of 2%;
(iii)
a spatial resolution of 3 line pairs per mm;
(iv)
IQI sensitivity - 2% of the joint thickness when wire
IQI's are to be used, the wire diameter axis shall be oriented
along the axis of the least sensitivity of the system.
(3)
Radioscopes are to be properly marked to co-relate with
particular part of joint represented.
(4)
The radioscopic examination data shall be recorded and
stored on videotape, magnetic disk or optical disk at the
maker's plant for a sufficient period after the date of
radioscopic examination as specified by the Inspecting
Authority, Efficient radioscopic examination record recall
shall be made available at any time over the record retention
period and shall be traceable to the test objects.
(5)
When repair has been performed as a result of
radioscopic examination, the repaired areas shall be
re-examined using the same radioscopic technique to evaluate
the effectiveness of the repair.
(6)
To aid in proper interpretation of the radioscopic
examination data, the details of the technique used shall
accompany the data. As a minimum, the information shall include the approved
procedure requirements and system performance test data.
Reg. 266 a
General
|
Any repair to a weld carried out by the manufacturer
shall first be agreed to by the Inspecting Authority.
Where defects occur in distributed positions in a seam,
repairs to the extent of 15 per cent. of the total length
of the seam shall be permitted to replace the defective
welding.
Where the defects are located in a single continuous
length, the permissible extent of repair shall be decided
by the Inspecting Authority.
|
Reg. 266 b
Longitudinal Seams
|
Where the weld metal in any way fails to comply with
the requirements specified the whole of the weld metal
may be removed and the seam re-welded provided that:
| i) |
the original test plates
are similarly treated, or |
| ii) |
new test plates of the
same thickness as the joint and of similar quality
of material are attached to the end of the seam
and re-welded with it. |
In either case the plates shall be tested in accordance
with Regulations
257 to 265
and the requirements for heat treatment shall be in
accordance with Regulation
267.
|
Reg. 266 c
Circumferential Seams
|
With regard to the extent of permissible repair and
when agreed by the Inspecting Authority a
circumferential seam shall be treated in the same manner
as a longitudinal seam. The Inspecting Authority shall
be entitled to call for representative tests for a
re-welded circumferential seam.
|
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